Mechanism of the alkaline hydrolysis of O-ethyl S-(2,4,6- trinitrophenyl) thio- and dithiocarbonates

ENRIQUE A. CASTRO; MARÍA CUBILLOS; JOSÉ G. SANTOS; ELBA I. BUJÁN; M. VIRGINIA REMEDI; MARIANA A. FERNÁNDEZ; RITA H. DE ROSSI

The Royal Society of Chemistry

Año: 1999 p. 2603 - 2603

he alkaline hydrolysis of O-ethyl S-(2,4,6-trinitrophenyl) thio- and dithiocarbonates, 1 and 2, respectively, were studied kinetically in 5% dioxane in water, at 25.0 C, and ionic strength 0.2 mol dm3 (KCl). Two kinetic rocesses, well separated in time, were detected. The fast process involves the formation of a σ-complex by addition of HO to one of the unsubstituted positions of the aromatic ring, followed by fast ionisation of this complex. The slow process leads to the formation of a mixture of 2,4,6-trinitrophenoxide and 2,4,6-trinitrobenzenethiolate ions in a 10 : 1 ratio, respectively, in the reaction of 2, and to a mixture in a 2 : 1 ratio in the reaction of 1, independent of KOH concentration. Although the substrates show different kinetic behaviour with KOH concentration, the results can be discussed on the basis of a common reaction mechanism.